POLICY ANALYSIS ASSUMPTIONS AND WHA

POLICY ANALYSIS ASSUMPTIONS AND WHAT WE
KNOW ABOUT FOREST ECOSYSTEMS
A number of policy proposals regarding management of
the National Forest System have recently been put forward.
Most of these proposals have embedded within them assumptions
about the workings of forest ecosystems and landscapes.
Sometimes such assumptions are explicitly identified, but more
often, the underlying assumptions are implicit and invisible
to many readers. In this section we have identified some of
these assumptions and examined them in light of the current
ecological knowledge outlined in the previous section. These include assumptions about forest stand dynamics, disturbances,
landscapes, and our ability to substitute for or replace
natural processes with active management programs.
The following analyses consider: 1) value of forest reserves
versus intensively managed forests, 2) whether silviculture can
substitute for natural forest processes, and 3) the role of timber
harvesting in forests managed for ecological values.
NATURAL STAND DYNAMICS, SUCCESSIONAL
CHANGE, AND DISTURBANCES: THE ROLE OF
FOREST RESERVES
A premise of many policy proposals, such as the Report
on Forest Health of the United States (Oliver et al. 1997), is
that the internal dynamics of forest stands that is, natural
successional change and the potential for natural disturbances
make it impractical to rely on forest reserves as the
centerpiece of programs to maintain biodiversity and other
important ecological functions society values on National
Forest lands. That is, since forest stands undergo changes in
species composition, structure, and functioning during succession,
these proposals assert that managers need to provide
for periodic cutting and replacement of such stands in
order to maintain valued ecological functions. Furthermore,
they assume that some natural disturbance such as wildfire,
windstorm, insects, or disease will eventually destroy the
existing stand and necessitate its replacement anyway.
Thus, many of these proposals call for elimination of reserve
status and the return of current reserves within the
National Forest system to the pool of intensively managed
lands. This would represent a major change in policy, as would
the opposite approach: establishment of extensive new areas
of reserves. We review here the definition, purpose, and value
of this land-use designation and the current debate over
whether natural forests are more vulnerable to disturbance
than intensively managed forests.